Snyder's of Hanover make REALLY good gluten free pretzels that taste just like gluten ones! Even my family can't tell the difference. Glutino also makes pretzels but I haven't tried those. You could also try glutino's table crackers which are kind of like saltines or their round crackers which are kind of like ritz.

I highly recommend the Snyder's pretzels though because they're almost identical to regular pretzels.

Try to relax about the procedure! I know each person's case is different, but I had a very positive experience! I was very nervous but my appointment wasn't until 4pm and at that point I was just ready to get it over with since I hadn't eaten or drank anything since 8pm the night before lol. Anyway, before I went back I wrote down a list of all of the questions I had and made sure to ask them to the nurse. From there, I got into a gown, got hooked to the IV, spoke briefly to the doctor, and then rolled down the hall to the procedure room. Once I got in there the anesthesiologist talked to me and was asking me about school and stuff. They put an oxygen mask over my face and told me that it was going to smell bad and then they gave me the anesthesia and I started getting really hot and then I started to panic because I couldn't ask them if I was supposed to feel hot because of the mask. That's the last thing I remember and honestly the worst part of the experience for me (and it wasn't even that bad.) When I woke up my parents were there and I had some ice cold water. They kept me for a little bit just to make sure I was good and then they let me leave and I got to go eat haha. From the time I woke up to the time I got home I only remember bits and pieces but it wasn't bad at all. I was actually feeling pretty good haha. Apparently I told my mom "these are some goooooooood drugs!" For the rest of that night my mouth was really dry and it was like I couldn't get enough to drink. The next day my throat was scratchy but it didn't really hurt.

It was my first time being drugged up and I was really nervous but it ended up being completely fine haha. If I had to do it again I wouldn't be nervous at all. Like I said, everyone is different but I think most peoples' experience with this have been fine.
Good luck! : )